I am curious about the definition of the well received question for the purposed of the Curious badge. For example, on Linux and Unix Stack Exchange I have several questions with a positive score, including two with a score of 2 (closed) and one with a score of 5, but overall I'm only seeing 2/5 for the Curious badge progress.

This is interesting to me, because I'm starting to wonder what 'well received question' might mean in this context. Might there, for example, be a specific formula that can be over-ridden under particular circumstances, or at the discretion of the mods? Or is the formula itself liable to change over time or when people decide their servers are a little bit bored.